A photosensitive composition contains a polymerizable compound having an ethylenically unsaturated bond and a photopolymerization initiator. A photosensitive composition polymerizes to cure on being irradiated with light of 405 nm or 365 nm and is used in photo-curing inks, photosensitive printing plate precursors, and various photoresists.
Patent documents 1 to 8 listed below propose using an O-acyl oxime compound having a carbazolyl structure as a photopolymerization initiator of a photosensitive composition. However, the known O-acyl oxime compounds are not sufficiently satisfactory particularly in sensitivity.    Patent document 1: JP 2001-302871A    Patent document 2: JP 2004-534797A    Patent document 3: JP 2005-25169A    Patent document 4: JP 2005-128483A    Patent document 5: JP 2005-242279A    Patent document 6: JP 2005-242280A    Patent document 7: JP 2006-16545A    Patent document 8: Japanese Patent 3754065